Light echoes around SN 1987A

CCD images of the double light echo around supernova SN 1987A, as observed with the ESO 3.6-metre telescope and EFOSC with a coronographic mask on 13 February 1988 (Ieft) and 16 March 1988 (right). A careful comparison shows the expansion, about 3 arcsec/month. Light echoes have been used as an efficient way of studying the structure of the interstellar medium close to the supernova. SN 1987A, detected in the nearby Large Magellanic Cloud, was the closest explosion of this kind for several centuries, the first visible by naked-eye for 383 years and definitely one of the most studied objects in modern astronomy. ESO telescopes have observed it for more than twenty years.